Microelectromechanical systems (“MEMS”) are used in a growing number of applications. For example, MEMS currently are implemented as gyroscopes to detect pitch angles of airplanes, and as accelerometers to selectively deploy air bags in automobiles. In simplified terms, such MEMS devices typically have a structure suspended above a substrate, and associated electronics that both senses movement of the suspended structure and delivers the sensed movement data to one or more external devices (e.g., an external computer). The external device processes the sensed data to calculate the property being measured (e.g., pitch angle or acceleration).
The electronics and suspended structure often are formed (by conventional etching processes) from the top layer of a multi-layered wafer. Problems arise during manufacture, however, when one portion of the top layer is electrically isolated from the remainder of the top layer, and/or not readily accessible to the edges of the device. In particular, from a design and manufacturing perspective, it is difficult to electrically connect such portion (referred to as an “island” or “isolated portion”) to other portions of the top layer. One solution to this problem is to snake an insulated line across the tortuous path leading to the isolated portion. This process generally is cumbersome, however, consequently increasing production costs.